Chemistry Chemistry 11.111.1““Describing Chemical Changes”Describing Chemical Changes”

ReviewReview

A. Reactants A. Reactants Products ProductsB. Dalton’s Theory…B. Dalton’s Theory…

““As reactants are converted to As reactants are converted to products, the bonds holding the atoms products, the bonds holding the atoms together are broken and new bonds are together are broken and new bonds are formed.”formed.”

C. Law of Conservation of Mass…C. Law of Conservation of Mass…““Mass is neither created nor destroyed.”Mass is neither created nor destroyed.”

II. EquationsII. Equations

A. Word EquationsA. Word Equations

1. Def – words used to describe a chemical 1. Def – words used to describe a chemical reaction.reaction.

-no #’s are involved-no #’s are involved

2. Ex: Iron + Oxygen 2. Ex: Iron + Oxygen Iron (III) Oxide Iron (III) Oxide

3. Ex: Hydrogen Peroxide 3. Ex: Hydrogen Peroxide Water + Oxygen Water + Oxygen

4. 4. Ex: Methane + Oxygen Ex: Methane + Oxygen Carbon Dioxide + water Carbon Dioxide + water

5. What is the word equation for…Pure 5. What is the word equation for…Pure copper can be produced by heating copper can be produced by heating copper (II) sulfide in the presence of copper (II) sulfide in the presence of diatomic oxygen from the air. Sulfur diatomic oxygen from the air. Sulfur dioxide gas is also a product in this dioxide gas is also a product in this reaction.reaction.

Copper II Sulfide + Oxygen Copper II Sulfide + Oxygen Copper + Sulfur Dioxide Copper + Sulfur Dioxide

B. Chemical EquationsB. Chemical Equations1. Def – Using chemical symbols to 1. Def – Using chemical symbols to write a chemical formula.write a chemical formula.

- #’s are involved- #’s are involved

2. Ex: Fe + O2. Ex: Fe + O22 Fe Fe22OO33

-this is a -this is a skeleton equationskeleton equation b/c it is b/c it is not not balancedbalanced

C. Balanced Chemical EquationsC. Balanced Chemical Equations

1. Follows the Law of Conservation 1. Follows the Law of Conservation of of Mass. Mass.

2. 2. 44 Fe + Fe + 33 O O22 22 Fe Fe22OO33

III. Symbols used in chemical equationsIII. Symbols used in chemical equations

+ Used to separate reactants or Used to separate reactants or productsproducts

““Yields” separates products and Yields” separates products and reactantsreactants

(s)(s) Solid state of matterSolid state of matter

(l)(l) Liquid state of matterLiquid state of matter

(g)(g) Gaseous state of matterGaseous state of matter

(aq)(aq) Aqueous solution – dissolved in Aqueous solution – dissolved in waterwater

∆ ∆ / heat/ heat Heat is supplied in the reactionHeat is supplied in the reaction

Pt, HPt, H22SOSO44A formula written above or below A formula written above or below

the yield sigh indicates it is a the yield sigh indicates it is a catalystcatalyst